Renal sclerosing peritubular nodule—how rare is it?

Neurofibromatosis type 2 (NF2) is a rare autosomaldominant disorder. It affects about 1 in 25 000 people. Approximately 50% of affected people inherit the disorder; in others the disorder is caused by a spontaneous genetic mutation of unknown cause. The hallmark finding in NF2 is the presence of bilateral vestibular schwannomas. Schwannomas may occur along any nerve in the body, including the spinal nerves, other cranial nerves and peripheral nerves. As these tumours grow, they may press against and damage nearby structures such as other cranial nerves and the brain stem; compression of the latter may cause serious disability. The gene for NF2 is a tumor suppressor gene located on chromosome 22q12. In contrast to NF1, cutaneous stigmata are generally lacking [1]. Kidney involvement in NF2 has not been studied extensively. A typical histological lesion caused smooth muscle proliferation in the wall of blood vessels, resulting in narrowing of the lumen and ultimately producing hypertension [2]. Rarely, schwannomas have been described in the renal pelvis and perirenal soft tissue [3, 4]. A relatively rare lesion, the renal sclerosing peritubular nodule (RSPN), was first described in a mother and two sons with NF2 who died and underwent autopsy in 1981 [5].